1. Field of the Invention
The present invention relates to an internal combustion engine and more particularly to a standard type internal combustion engine with pistons, operating on the stratified charge principle resulting in non-polluting combustion of the fuel-air mixture forming the charge.
2. Description of the Prior Art:
The stratified charge principle consists of forming in the engine combustion chambers, at the instant of ignition, a mixture of heterogeneous richness, rich in the vicinity of the spark plug and lean in the rest of the chamber. The easy ignition by the plug of the pocket of rich mixture surrounding it starts the combustion which then spreads to the remaining lean mixture. The result is complete final combustion because of the low over-all richness of the whole charge.
Different ways are known to the prior art for obtaining such charge and stratified combustion. One such method is to introduce the rich mixture into a precombustion chamber next to the cylinder with which it communicates, the spark plug facing into this precombustion chamber with the lean mixture being simultaneously introduced into the cylinder in the normal way. In such case, the configuration of the chambers and the adjustment of the dual inlet of the rich and lean mixtures assures stratification. This method is effective, but it has proven to be costly because of the use of a complex cylinder head, timing system and fuel feed.
Another known way of stratification is that done directly into the combustion chamber, either by injecting fuel near the spark plug in the center of an air swirl, or, as in the French Pat. No. 70/34,461 of Sept. 3, 1970, in the applicants' name, by admission of a charge pre-stratified in the exit of the inlet manifold with the layer of richest mixture being directed at the spark plug. Effective adjustment of stratification by direct injection of fuel has not been possible as of yet and the pre-stratification in the inlet, though a very economical solution, is not readily adaptable to different types of motors and the stratification effect in such method is limited.